This invention relates to the control of turbomachines and, in particular, relates to a valve operator for opening and closing inlet valves to the turbomachine.
In a prime mover, for example, a steam turbine, the steam inlet valve is hydraulically controlled by a valve operator. The valve operator is required to open and close the steam inlet valve in response to a valve command input and, moreover, the valve operator must be able to rapidly shut the steam inlet valve in response to a trip command. The valve operator should be capable of receiving a valve command input from a remote location. For example, for a marine steam turbine it is desirable to be able to control the valve operator and steam inlet valve from a bridge location as well as from the engine room. Moreover, it is also required that the valve operator be manually operable in the event that remote control fails.
The present invention satisfies the foregoing specification in the following manner. The valve operator includes a manifold having a valve actuating piston slidable therein, said piston being attached to the steam inlet valve. The piston is hydraulically positionable by a pilot valve. The pilot valve is positioned by a lever which is attached at one end to a linearly movable fulcrum and connected at the other end to the valve actuating piston. The fulcrum is movable by a manual or remote controlled powered operator. The valve operator further includes a trip relay and a reset pilot, said relay and reset pilot being interconected by a fluid passage so that the reset pilot must be reset prior to resetting the trip relay. The lever interconnecting the fulcrum, pilot valve and piston also positions the reset pilot.
It is an object of the present invention to provide a valve operator which may be used to control a turbomachine inlet valve and includes a trip relay for rapidly closing said valve.
It is another object of the present invention to provide a valve operator which may be remotely operated and manually operated.
The novel features believed characteristic of the present invention are set forth in the appended claims. The invention itself, however, together with further objects and advantages thereof, may best be understood with reference to the following description, taken in connection with the appended drawing.